Richard J. wrote:

(snip)

The NLL (not NNL) is also fairly unreliable in my experience.


NLL being the North London Line, currently operated by Silverlink
Metro.

I'm an occasional user of the NLL, I find that the trains are often
delayed by a few minutes but cancelations are rare - unless that is
there's some major problem somewhere - and once you're on the train it
doesn't get held up by anything else. After all it is an every 15
minute (or every 20 in the evening) metro service that carries a lot of
people these days.